Defense Secretary James Mattis has announced that transgender military personnel already in service can continue to serve in the United States military while an expert panel reviews ways to implement President Donald Trump's request to ban transgender Americans from openly serving.

On Tuesday, Mattis released a statement explaining that he is going to create "a panel of experts" that will work with the Department of Defense and the Department of Homeland Security to provide recommendations on the implementation of Trump's recent call to ban transgender Americans from serving in the military.

"Panel members will bring mature experience, most notably in combat and deployed operations, and seasoned judgment to this task," Mattis' statement reads. "The panel will assemble and thoroughly analyze all pertinent data, quantifiable and non-quantifiable."

Mattis stressed that the Defense Department will "develop a study and implementation plan, which will contain the steps that will promote military readiness, lethality, and unit cohesion, with due regard for budgetary constraints and consistent with applicable law.

"The implementation plan will address accessions of transgender individuals and transgender individuals currently serving in the United States military," the secretary's statement reads. "Our focus must always be on what is best for the military's combat effectiveness leading to victory on the battlefield."

Mattis explained that once he has received recommendations from the panel, then he will advise the president about the "implementation of his policy direction."

"In the interim, current policy with respect to currently serving members will remain in place," Mattis said. "I expect to issue interim guidance to the force concerning the president's direction, including any necessary interim adjustments to procedures, to ensure the continued combat readiness of the force until our final policy on this subject is issued."

Last Friday, Trump sent the Departments of Defense and Homeland Security a presidential memorandum titled "Military Service by Transgender Individuals." The memorandum explained that up until last July, the U.S. military's policy was to not allow transgender individuals to openly serve.

Trump said the move by former Defense Secretary Ash Carter to end the ban on transgender service members had "dismantled the Departments' established framework." The president also criticized the policy for "authorizing the use of the departments' resources to fund sex-reassignment surgical procedures."

The president ordered the Departments of Defense and Homeland Security to "return to the longstanding policy and practice" on transgender identity that was in place prior to June 2016 "until such time as a sufficient basis exists upon which to conclude that terminating that policy and practice would not have the negative effects discussed above."

The memorandum explains that after consulting with Homeland Security Secretary John Kelly, Mattis can advise the president "at any time" that "a change to this policy is warranted."

"In my judgment, the previous Administration failed to identify a sufficient basis to conclude that terminating the departments' longstanding policy and practice would not hinder military effectiveness and lethality, disrupt unit cohesion, or tax military resources, and there remain meaningful concerns that further study is needed to ensure that continued implementation of last year's policy change would not have those negative effects," the president's memorandum reads.

Trump initially announced that he would ban transgender individuals from serving in the military in a series of tweets from late July.

While LGBT advocates have decried the idea of banning transgender individuals from serving in the military, social conservative advocates have claimed that doing so would improve military readiness.

A group of retired flag-rank military officers that included Family Research Council Executive Vice President Jerry Boykin sent Trump a letter following his tweet to express their gratitude for Trump's desire to do away with the Obama-era policy.

"Even if it can be scientifically demonstrated that gender reassignment procedures medically benefit some individuals, there will still be concerns about the deployability of these individuals," the letter reads. "DoD guidelines require that those serving in the military be 'medically adaptable to the military environment without the necessity of geographic area limitations.' However, both hormone therapy and gender reassignment surgery result in the need for specialized medical care which will not be available in all geographic locations."

"Aside from the time lost due to the non-deployability of the person transitioning, one must also consider the time taken away from commanding officers for transgender case management. The detailed assessment and management of these complex cases by commanders would have been substantial," the letter continues. "Needless to say, that is time not being spent training or thinking about how to engage and defeat our enemies in combat. The shifting of CO time would have been a real detriment to military effectiveness."

On Wednesday, Sen. John McCain, R-Ariz., a former Navy captain, praised Mattis' statement in a tweet.

"Glad Sec Mattis is taking time to create and review a Pentagon study to develop a plan on transgender military service," the tweet reads.